On Mar 14, 9:42*am, willshak wrote:
Eric Keller wrote the following:

My first post to this group so please forgive me if this has been
asked and answered.

I plan on burying my downspouts and having them merge into one 4"
drain pipe. The discharge will be at a nice point far from my house.
The length will be about 200 ft from the first downspout to the
discharge. There will be a total of 4 downspouts merging into the same
line.

My question is: How many downspouts can I run into a single 4" PVC
pipe within the 200 ft length? I live near Chicago and we get plenty
of rain.

Thanks.

I have two roofs on my 60' long house, one higher than the other. The
one end of the house has level ground, the other has a fairly steep
slope dropping away from the house. *The upper roof gutter drains toward
the sloped side of the house, and when it reaches the end of that roof,
it drops via downspout to the lower roof's gutter, then into the lower
roof gutter, then along that lower gutter to the sloped side of the
house. It then drops down a downspout to the ground and into a 4"
plastic elbow connected to a 4" pipe which exits about 30' downhill from
the house. It's been there for 26 years with no problem, except for the
chipmunks occasionally building nests in the pipe, but they are flushed
with the rains.. The same type system is at the opposite side of the
houser, so we're talking about 120' of gutters between the 2. It has
never rained hard enough to overflow the gutters, unless blocked by
leaves or debris, which can happen to any length of gutter that is not
cleaned regularly.

Without doing a lot of math, I doubt whether 4 downspouts draining into
a single 4"' pipe would cause a problem with a standard sized house.
Math would give you the total volume of each downspout x 4, and the
total volume of a 4" pipe, and even if the volume of the 4 downspout is
more than the volume of the pipe, the downspouts rarely, if ever, have
to deal with a full volume of dropping water. If it ever does, somebody
better be building an Ark.
I have checked the flow of water from the 4" round pipe during a hard
rain, and the depth of the water coming out was about 1" to 1-1/2" deep
from each of *the two gutters

--

Bill
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeroes after @

Bill,

Thanks. Feeling much better about my decision. I thought about going
up to 6" pipe after the second downspout or even running two separate
lines each taking on two downspouts. But all that is too much work..
and material. I do think that 4 downspouts running into one 4" pvc
line is adequate. Your experience helps me make my decision.